Image forming method and apparatus capable of effectively performing charging operation

Abstract

An image forming apparatus includes image forming units, a toner supply device, a common-unit detection device, an initial operation execution device, and a determination device. Each image forming unit is detachably provided in the image forming apparatus, and includes at least a development device containing toner. At least two of the image forming units are common image forming units having a common structure. When the common-unit detection device detects a common image forming unit at installation thereof, the initial operation execution device supplies a predetermined amount of toner to a development device of the common image forming unit and mixes to charge the toner by friction for a predetermined time period. Then, the. determination device detects whether the toner in the development device is charged to a predetermined level, and determines, based on the detection, whether to mix the toner one more time for another predetermined time.

1. An image forming apparatus, comprising:
 a plurality of image forming units detachably provided in the image forming apparatus and including at least two common image forming units having a common structure, each including a development device; 
 a toner supply device configured to supply toners of different colors to corresponding development devices of the plurality of image forming units; 
 a common-unit detection device configured to detect each one of the at least two common image forming units at installation thereof; 
 an initial operation execution device configured to execute an initial operation of supplying an amount of toner to a development device of each one of the at least two common image forming units detected by the common-unit detection device and mixing to charge the toner by friction for a preset time period before a formation of a reference image on an image carrier; and 
 a determination device configured to detect a status as to whether the toner in the development device is charged to a threshold level upon completion of the initial operation, and to determine whether to mix the toner one more time for another time period based on the status detected. 
 
   
   
     2. The image forming apparatus as described in  claim 1 , further comprising:
 a plurality of image carrying members; and 
 a plurality of density detection devices each configured to detect a density of a reference toner image pattern formed on a corresponding one of the plurality of image carrying members, 
 wherein the determination device detects a status as to, based on the density detected, whether the toner in the development device is charged to the threshold level upon completion of the initial operation. 
 
   
   
     3. The image forming apparatus as described in  claim 2 , wherein each one of the plurality of image forming units comprises a non-volatile memory configured to store information based on which the common-unit detection device detects the one of the at least two common image forming units at installation thereof. 
   
   
     4. The image forming apparatus as described in  claim 3 , wherein, when the determination device determines not to mix the toner one more time, the non-volatile memory stores information that an initial setting operation has completed. 
   
   
     5. The image forming apparatus as described in  claim 4 , wherein the non-volatile memory is configured to store information that the initial setting operation is proceeding while the initial operation is executed by the initial operation execution device. 
   
   
     6. The image forming apparatus as described in  claim 4 , wherein, when the common-unit detection device detects a non-common image forming unit at installation thereof, whether the non-common image forming unit is installed at an appropriate position in the image forming apparatus is detected. 
   
   
     7. The image forming apparatus as described in  claim 6 , wherein one of the plurality of image forming units is supplied with a black toner and is different in structure from the other plurality of the image forming units. 
   
   
     8. The image forming apparatus as described in  claim 7 , wherein each one of the plurality of image forming units comprises a toner density detection device configured to detect a toner density of toner contained in the development device thereof. 
   
   
     9. The image forming apparatus as described in  claim 8 , wherein toner supply is controlled based on the toner density detected by the toner density detection device. 
   
   
     10. The image forming apparatus as described in  claim 9 , wherein a toner supply state is detected based on the toner density detected by the toner density detection device. 
   
   
     11. An image forming apparatus comprising:
 a plurality of image forming means for forming toner images of different colors, the plurality of image forming means including at least two common image forming means having a common structure; 
 toner supplying means for supplying toners of the different colors to corresponding development means of the plurality of image forming means; 
 common-unit detecting means for detecting each one of the at least two common image forming means at installation thereof; 
 initial operation executing means for executing an initial operation of supplying an amount of toner to developing means of each one of the at least two common image forming means detected by the common-unit detecting means and mixing to charge the toner by friction for a preset time period before a formation of a reference image on an image carrier; and 
 determining means for detecting a status as to whether the toner in the development means is charged to a threshold level upon completion of the initial operation, and for determining whether to mix the toner one more time for another time period based on the status detected. 
 
   
   
     12. An image forming method comprising:
 providing a plurality of image forming units including at least two common image forming units having a common structure, each including a development device; 
 confirming installment of each one of the at least two common image forming units in the image forming apparatus; 
 executing an initial operation of supplying an amount of toner from a toner supply device to a corresponding development device of each one of the at least two common image forming units confirmed as installed in the confirming step and mixing to charge the toner by friction for a preset time period before forming of a reference image on an image carrier; 
 detecting a status as to whether the toner in the development device is charged to a threshold level upon completion of the initial operation; and 
 determining whether to mix the toner one more time for another time period based on the status detected. 
 
   
   
     13. The image forming method as described in  claim 12 , wherein the detecting step comprises: forming a reference toner image on an image carrying member corresponding to the development device; and detecting a density of the reference toner image used as a basis for detecting the status. 
   
   
     14. The image forming method as described in  claim 13 , wherein the confirming step comprises: referring to information stored in a non-volatile memory of each one of the plurality of image forming units as a basis for confirming the installation. 
   
   
     15. The image forming method as described in  claim 14 , further comprises: storing, in the non-volatile memory, information that an initial setting operation has completed, when it is determined unnecessary to mix the toner one more time. 
   
   
     16. The image forming method as described in  claim 15 , further comprises: confirming installing of a non-common image forming unit in the image forming apparatus; and detecting whether the non-common image forming unit is installed at an appropriate position in the image forming apparatus. 
   
   
     17. The image forming method as described in  claim 16 , wherein one of the plurality of image forming units is supplied with a black toner and is different in structure from the other plurality of the image forming units. 
   
   
     18. The image forming method as described in  claim 17 , further comprises: detecting a toner density of toner contained in the development device of the each one of the plurality of image forming units. 
   
   
     19. The image forming method as described in  claim 18 , further comprises: controlling toner supply based on the toner density detected in the toner density detecting step. 
   
   
     20. The image forming method as described in  claim 19 , further comprises: detecting a toner supply state based on the toner density detected in the toner density detecting step.